Instrument knob having integral detent mechanism and panel mount socket means

ABSTRACT

A rotary instrument knob with integral detent and stop means. An integral bushing or &#39;&#39;&#39;&#39;termination socket&#39;&#39;&#39;&#39; is provided whereby the knob may be assembled onto a panel in a rotationally predetermined orientation. The detent mechanism includes an indentation contour on a flange end of the termination socket within the knob body. The knob body is constructed in sections whereby the assembly of stop rings, detent balls and spring retaining means may be accomplished and then enclosed within the knob body by snap-fit assembly of the knob body shell over those elements.

United States Patent Kroll et al. May 16, 1972 [54] INSTRUMENT KNOBHAVING 3,198,923 8/1965 Tripp ..74/553 ux INTEGRAL DETENT MECHANISM AND3,517,570 6/l970 Kolb i ..74 527 PANEL MOUNT SOCKET MEANS Inventors:Heinz Ernst Johannes Kroll, Heroldsberg; Horst Dieter Ziegler, Numberg,both of Germany Assignee: International Standard Electric Corporation,New York, NY.

Filed: May 27, 1970 Appl. No.: 40,885

Foreign Application Priority Data July 31,1969 Germany ..P 19 27 901.7

U.S. Cl ..74/527, 74/553, 116/115 ....G05g 5/06 Field of Search..74/527, 5 5 3 References Cited UNITED STATES PATENTS 2,840,672 6/1958Martin ..74/527 3,541,882 ll/l970 Testa ..74/553 Primary ExaminerWilliamF. ODea Assistant Examiner-F. D. Shoemaker Att0rneyC. Cornell Remsen,Jr., Walter J. Baum, Paul W. Hemminger, Percy P. Lantzy and Thomas E.Kristofferson A rotary instrument knob with integral detent and stopmeans. An integral bushing or termination socket" is provided wherebythe knob may be assembled onto a panel in a rotationally predeterminedorientation. The detent mechanism includes an indentation contour on aflange end of the termination socket within the knob body. The knob bodyis constructed in sections whereby the assembly of stop rings, detentballs and spring retaining means may be accomplished and then enclosedwithin the knob body by snap-fit assembly of the knob body shell overthose elements.

ABSTRACT 10 Claims, 3 Drawing Figures INSTRUMENT KNOB HAVING INTEGRALDETENT MECHANISM AND PANEL MOUNT SOCKET MEANS on its side facing theapparatus, is provided with a hollow v space for receiving an arrestingor click-stop device serving to fix the positions of rotation of theshaft. Such types of rotary knobs are required above all for rotaryswitches comprising a control knob mounted to the control shaft thereof,and by which certain switching positions of the shaft can be adjusted.

The fixing or arresting of switching positions of a control shaft, as iswell known, is effected with the aid of a click-stop or arresting devicewhich is joined to the apparatus to be operated, or which, e.g., may bebuilt into the apparatus. In conventional types of rotary switches thisclick-stop device consists of biassed or pretensioned balls which, forthe purpose of effecting their engagement, are provided with fixedarresting positions. It may, for example, be surrounded by a spacingportion forming part of the housing, whereas the remaining parts of thehousing are composed of stator parts which are piled on top of eachother, surrounding the shaft. Electric rotary switches of this type andconstruction have already been extensively miniaturized, in that theparts thereof are being designed very small. This miniaturization,however, can only be carried out within certain limits in view of theoccurring actuating forces, even if the latter are being kept as smallas possible, because there have to be avoided any unwanted variations orchanges in shape of the switch, or of the parts which are important forperforming the functions thereof, respectively. The result of this isthat known types of rotary switches cannot be further reduced in size.

For avoiding this disadvantage is has already been proposed to providein the rotary knob of the rotary switch a hollow space which, on itsside facing the apparatus to be operated, is designed as an engagingcontour in which the hold members slide which, in turn, are guided by anengaging or arresting body which is arranged in this hollow space. Thisengaging or arresting body, at the same time, is provided with means forallowing it to be mounted to the apparatus.

The foregoing proposal was based on the consideration that the rotaryknob, for serving as a handle, must have a certain size, but that thespace enclosed thereby, is not fully utilized, whereas the apparatusitself is supposed to be of a space-saving construction. The presentinvention is based on the same consideration and has for its object toprovide a rotary knob suitable for being mounted to a shaft and which,at the same time, contains a click-stop device, so that it will thusbecome possible for certain devices in which a shaft is to be turned oradjusted, to be miniaturized to very small dimensions. According to theinvention, and with respect to a rotary knob of the type mentionedhereinbefore, this is accomplished in that the engaging member of theclick-stop device is a termination socket which is provided with ashaft-passage opening and is joined to a rotary knob in the axialdirection, with this termination socket, on its side facing theapparatus, is provided with means allowing to be mounted to theapparatus and, on its side not facing the apparatus, is designed tocarry an engaging contour in which resiliently supported holding(engaging or arresting) members which are guided by a holding body(guide ring) which is coupled in a motion-locking fashion to the shaft,are permitted to slide.

The invention offers the advantage, according to which it is possible,merely by interchanging the rotary knob, to provide certain devices inwhich a control shaft is to be fixed or engaged in predetermined rotarypositions, with a click-stop or arresting device. In so doing, it isstill possible, as up to now, for the rotary knob to be mounted from oneside. A further advantage capable of being achieved by the invention,resides in the fact that such types of devices may have very smalldimensions which they are required to have, for example, when intendedto be built into printed circuit boards.

Moreover, the present invention offers the advantage that a limitingstop function which might be required in certain cases, may be replacedfrom the apparatus into the rotary knob, thus resulting in a furthersaving of space in the apparatus. According to an advantageous furtherembodiment of the invention, this is accomplished in that into thehollow space of the rotary knob there is inserted a limiting stop devicewhich, in a motion-locking fashion, is joined thereto, and with the aidof which it will become possible to prevent the shaft from being turnedbeyond a predetermined angle.

For the purpose of enabling a better understanding of the invention,these and advantageous further embodiments of the invention will now bedescribed in detail with reference to an example of embodiment shown inFIGS. 1 to 3 of the accompanying drawings in which:

FIG. 1 shows a longitudinal section taken through a rotary knobcomprising a click-stop device and a limiting-stop device according tothe invention;

FIG. 2 shows a top view taken in the direction indicated by the arrow A,of this rotary knob, with the front plate or panel removed, and

FIG. 3 shows a cross section taken along line B-C taken through therotary knob shown in FIG. 1.

According to H6. 1, the shown rotary knob 10 comprises an internalhousing 20 and an external housing surrounding the latter at leastpartly in a form-locking manner, and composed of three parts 30, 40, 50capable of being placed on top of each other, with the reference numeral30 indicating the bottom of the housing carrying the internal housing,and with the reference numeral 40 indicating the sleeve of the housingprovided with corrugated handling areas 41, and with the referencenumeral 50 indicating the cover of the housing (housing cap) terminatingthe sleeve of the housing at the top end. By means of a resilientholding or retaining pawl 51 this housing cap is detachably latched tothe sleeve of the housing 40. The bottom of the housing 30 meets withone face sided end against the neighboring face side of the sleeve ofthe housing 40 and is likewise detachably mounted in the internalhousing by means of a snap-action joint. To this end the detachablebottom of the housing 30 is provided on its inside with a circulargroove 31, and the internal housing 20 is provided on its outside facingthe bottom of the housing, with a circular cam 21 fitting into thecircular groove 31. An indicator 32 molded to the bottom of the housing30 serves to indicate the respective rotary position of the rotary knob10. For readjusting and fixing in position of the indicator 32, thecircular cam 21 is provided along its circumference with slots 22arranged in an angular division corresponding to the engaging positionsof the rotary knob 10, with these slots 22 capable of being engaged by aradial inwardly directing nose portion 33 as molded to the innercircumference of the detachable bottom part 30 of the housing.

The mechanical connection between the sleeve of the housing 40 and,consequently, of the rotary knob 10 and the control shaft 60 of theapparatus to be operated, is effected via a collet or holding fixture 70which is provided with a shaftpassage opening 71, which is accommodatedin a hollow space 23 not facing the apparatus, and forming part of theinternal housing 20. To this end the sleeve of the housing 40 comprisesa collar 42 extending into this hollow space, to which the tightening ortension nut of the collet or holding fixture 70 is pressed via a shimplate (washer) arranged therebetween.

Both the tightening (or tension) nut 80 and the shim plate (or washer)90 are arranged in a hollow space 52 of the housing cap 50 or in ahollow space 43 adjacent the housing cap, of the sleeve of the housing40 respectively. Since the shim plate 90, in turn, is lying closelyagainst one neighboring face side of the sleeve of the housing 40, thissimultaneously establishes a mechanical connection between the internalhousing 20 and the external sleeve of the housing 40.

Besides the collet or holding fixture 70, i.e., parts of the arrangementfor efiecting the axial fixing, the internal housing 20 contains theentire click-stop or arresting device for retaining the positions ofrotation. As an engaging or arresting member of the click-stop orarresting device there is used a termination socket 100 which isconnected to the rotary knob in the axial direction, and is providedwith a shaft-passage opening 101, hence which has to be supportedstationarily, e.g., on the front panel 110 of the apparatus to beoperated. For this purpose the termination socket 100 comprises one partprojecting out of the internal housing 20, on which means are providedfor allowing mounting to the apparatus. In the example of embodimentshown in FIG. 1, therefore, there are provided on this part, a shoulder102 resting against the front panel 110, and a circular groove 103arranged before the shoulder, for receiving a not shown guard orretaining plate. In order to avoid relative movements between thetermination socket 100 and the front panel 110 of the apparatus, thetermination socket is moreover provided with a stop element 104 which,for example, is designed to have the shape of a nose engaging the frontpanel. On the side not facing the apparatus, hence in the inside of theknob, the stop element 104 may simultaneously serve as a stationarylimiting stop for restricting the rotary movement of the control shaft60. The shown stop member 104 enables a particularly simpletorsion-proof mounting of the termination socket 100 to the apparatus orthe front panel 110 thereof respectively, because during assembly of therotary knob 10, the stop member merely has to be inserted into acorresponding recess provided in the front panel. The necessarytorsional resistance, however, may also be obtained in any other way,for example, by providing a recess in the termination socket 100 whichis then engaged by a nose or engaging portion arranged on the frontpanel 110 of the apparatus. The termination socket 100 can also bejoined in a completely different way to the apparatus, for example, byway of screwing or cementing (glueing). The axial adherence between thetermination socket 100 and the control shaft 60 is secured by a guard orretaining ring 120 which is arranged in an annular groove 24 of theinternal housing 20, lying closely against a collar 105 of thetermination socket within the range of its face side pointing into thehollow space 27 of the internal housing.

In order to achieve an engaging or arresting turning of the rotary knob10, it is necessary to provide the termination socket 100 acting as theengaging or arresting member, with an engaging or arresting contour 106.This engaging contour in which holding or engaging members slide whichare resiliently supported and retained and guided in a suitable way, isarranged on the face side of the termination socket 100 not facing theapparatus or the front panel 1 10 thereof respectively. As suitable holdor engaging members there may be considered, in particular, balls 130,140. The holding body guiding these balls, is designed to have the shapeof a ring 150 surrounding the control shaft 60 and in the circularrecesses of which the balls are supported. In order to ensure that thisguide ring 150 is being taken along by the housing capable of rotatingabout the termination socket 100, when actuating the control shaft 60,it is designed to engage with its segmentshaped projections 15] asarranged along its outer circumference, the correspondingly adaptedcutouts or recesses as arranged on the inside of the housing 20.

By a finger (finger-shaped projection) 152 extending inwardly andarranged on the inner circumference of the guide ring 150, and which, ina form-locking manner, engages a longitudinal groove on the controlshaft 60, both the engaging and the shaft position can be fixed inrelation to one another. To this end, also the inner circumference ofthe guide ring 150 may be adapted to the profile of the control shaft,e.g., a flat shaft. This might be of significance, for example, in caseswhere rotors are mounted on the control shaft 60 which are intended tobe turned as well, and carry contact members, which in turn, cooperatewith stator contact members by performing a corresponding opening andclosing. Upon actuating the control shaft 60, the balls 130, 140 areadvanced in a step by step manner from engaging point to engaging point,for fixing thus the position of rotation of the shaft, and for bringingcertain stator and rotor contact members into or out of contactrespectively. The arrangement of the rotors and stators and of thecontact members thereof can be made in the usual way, and is of nosignificance to the present invention.

In the example of embodiment according to FIG. 3 two diametricallyopposing, circular openings are arranged in the guide ring at an equallyspaced relation from the shaft 60. In this way it is accomplished thatthe engaging or arresting pressures of the two balls 130, 140, willannul each other with respect to the loading of the control shaft 60. Inorder to produce the necessary engaging pressure, a ball-retaining diskwhich is provided with a shaft-passage opening, is placed by a flexibledevice against the balls 130, 140. This is accomplished with the aid ofa helical compression spring which is retained and guided concentricallyin relation to the shaft 60 in a circular groove 26 as provided in thehousing 20, and extending in the axial direction. This helicalcompression spring thus presses the balls 130, 140 against the face sidewall of the termination socket 100 and, consequently, against theengaging contour 106. By the holding arrangement of the helicalcompression spring 170 which is permanently concentrical in relation tothe shaft 60, the ball-retaining disk 160 is uniformly pressed againstthe balls 130, 140, thus resulting in a particular precise andeasy-going engagement or arresting in all positions of rotation of therotary knob 10 at the required actuating moment. The invention, ofcourse, is in no way restricted to the feature of employing two suchengaging or arresting members only. Moreover, it is equally wellpossible to employ rollers instead of the balls as holding, engaging orarresting members.

In order to restrict the rotary motion of the control shaft 60, thereare provided the limiting-stop rings 180, 190 which, with segment-likeprojecting portions 181 (or 191 respectively) as arranged along theouter circumference thereof, engage the correspondingly adapted recessesor cutouts 25 on the inside of the housing 20. Appropriately, there areused two such limiting-stop rings 180, 190 which, as may be taken fromFIG. 1, are placed on top of each other, and are capable of being turnedby a certain angular division with respect to the housing of the rotaryknob. On their inner circumference, these two limiting-stop rings 180,190 each comprise an inwardly extending arresting catch 182 or 192respectively. These two arresting catches 182, 192 together form anangle which is determined by the number of desired positions of rotation(switching positions), and cooperate with a stationary limit stop, suchas the stop element 104, in the sense of restricting the rotary motionof the control shaft 60 in both directions. For example, in the case ofa l2-position click-stop device, there is used a'limiting-stop device inwhich the two arresting catches 182, 192 together form an angle of 30.By differently inserting the two limiting-stop rings 180, 190, however,it is possible to readjust the limit stops in any arbitrary fashion.Moreover, the limit stop may also be completely omitted by removing therings 180, 190. It is also possible to use one single ring instead oftwo such rings, which then comprises two arresting catches 182, 192. Inthis case, of course, the distance or spaced relation between thelimiting stops can no longer be readjusted. In cases where only onelimit stop is provided, one such limiting-stop ring or with onearresting catch 182 or 192 is sufiicient. In this case the shaft 60 canonly be turned by 360, with the respective arresting catch 182 or 192for restricting the rotary motion, appearing on opposite sides of thestationary limiting stop, e.g., at the stop element 104.

The axial fixing of the limiting-stop rings 180, 190 in relation to thecontrol shaft 60 is effected, on one hand, by the guard or retainingdisk 120 as arranged inside the housing 20 of the rotary knob and, onthe other hand, by the inwardly projecting joined-on portion 34 of thebottom of the housing 30. For readjusting the limiting-stop rings 180,190 it is then merely necessary for the bottom of the housing 30 to beremoved temporarily; this, however, will not affect the functioning ofthe click-stop or arresting device.

The rotary knob 10 according to the invention can be mounted in theusual way to a control shaft 60. It is merely required to provide anysuitable kind of device for preventing the termination socket 100 frombeing turned. As already mentioned, this means for preventing a rotationcan be formed by a recess or cutout provided in the front panel 110 ofthe apparatus. Alone by the employment of one rotary knob according tothe invention, switches or other devices capable of being operated by ashaft, can be provided with a click-stop or engaging device.

The rotary knob as shown in FIGS. 1 to 3 can be made of any suitablematerial. Preferably, however, the three outer parts of the housing ofthe rotary knob 10, i.e., the bottom 30, the sleeve 40, and the cap 50of the housing are made from a suitable injection molded plasticmaterial, whereas the internal housing 20, as well as the terminationsocket 100 are made from a die-casting zinc alloy (injectiommolded ordie-cast zinc).

What is claimed is:

1. A rotary shaft control instrument knob having self-containeddetenting mechanism within the body of said knob, comprising: atermination socket in the form of a bushing having a flanged end and abore therethrough coaxial with the axis of rotation of said knob toaccept the said shaft to be controlled, with rotational freedom, saidsocket being adapted to be inserted and retained partly through anopening in a panel with said flanged end projecting into the interior ofsaid knob body; means for retaining said knob body against substantialaxial movement while permitting rotation thereof with respect to saidtermination socket; shaft lock means within and rotationally keyed tosaid knob body for securing rotational continuity between said knob andsaid shaft; detent means comprising a series of indentationsconstituting an engaging contour distributed circumferentially about theface of said flange, and at least one rolling member of circular crosssection in at least one plane operative against said indentations;resilient means operating against the inside of said knob body formaintaining a compressive force between said rolling member and saidflange; guide means keyed to said knob body for impartingcircumferential motion to said rolling member as said knob and saidshaft are rotated together, whereby said rolling member tends to seat insuccessive ones of said indentations to produce detenting at positionscorresponding to predetermined angular positions of said knob and shaft.

2. Apparatus according to claim 1 including a keying arrangement betweenthe external body of said socket and the perimeter of said opening forretaining said termination socket within said opening in said panel andfor locking said socket in place rotationally.

3. Apparatus according to claim 2 in which said retention of said socketin said opening is effected by a locking ring inserted in acircumferential slot in the external perimeter of said socket, said ringbearing against said panel on the side thereof opposite the installationof said knob, and in which said socket includes a shoulder bearingagainst said panel on the opposite side thereof, whereby said socket isaxially locked in position.

4. Apparatus according to claim 1 including an at least partiallyradially outwardly projecting finger connected to the outer perimeter ofsaid socket within said knob body and at least one stop ring keyed tosaid knob body and having at least one radially inwardly projectionoriented to engage said outwardly projecting finger at a predeterminedangular position of said knob and shaft.

5. Apparatus according to claim 1 having two of said stop rings stackedaxially and each having multiple peripheral keying means whereby theymay be separately keyed to said knob body to provide first and secondangular limits of operation of said knob and shaft.

6. Apparatus according to claim 4 in which said knob body is composed ofat least two axially assembled hollow parts, a first of said partscontaining said stop ring, whereby said knob may be assembled byemplacing said first part in proximate position over said panel openingand inserting said socket through said first part and said panel.

7. pparatus according to c aim 6 including a second hollow knob bodypart axially snap-fitted into said first part, said second partincluding an internal surface in a plane normal to the axis of said knobto face said termination socket flange to carry said resilient meansbearing against said circular cross section member.

8. Apparatus according to claim 7 in which said shaft lock means areincluded in said second part, whereby said knob may be further assembledby emplacing said rolling member of circular cross section against saidengaging contour and emplacing and locking said second part to saidshaft thereby bringing said resilient means to bear against saidcircular cross section member.

9. Apparatus according to claim 8 having at least two circular crosssection members substantially diametrically opposite in position alongsaid engaging contour and said members are balls.

10. Apparatus according to claim 9 in which said resilient meanscomprises a pressure ring inserted against said balls opposite saidengaging contour and a helical spring bearing against said pressure ringand caged in an annular groove inside said knob body second part.

1. A rotary shaft control instrument knob having self-containeddetenting mechanism within the body of said knob, comprising: atermination socket in the form of a bushing having a flanged end and abore therethrough coaxial with the axis of rotation of said knob toaccept the said shaft to be controlled, with rotational freedom, saidsocket being adapted to be inserted and retained partly through anopening in a panel with said flanged end projecting into the interior ofsaid knob body; means for retaining said knob body against substantialaxial movement while permitting rotation thereof with respect to saidtermination socket; shaft lock means within and rotationally keyed tosaid knob body for securing rotational continuity between said knob andsaid shaft; detent means comprising a series of indentationsconstituting an engaging contour distributed circumferentially about theface of said flange, and at least one rolling member of circular crosssection in at least one plane operative against said indentations;resilient means operating against the inside of said knob body formaintaining a compressive force between said rolling member and saidflange; guide means keyed to said knob body for impartingcircumferential motion to said rolling member as said knob and saidshaft are rotated together, whereby said rolling member tends to seat insuccessive ones of said indentations to produce detenting at positionscorresponding to predetermined angular positions of said knob and shaft.2. Apparatus according to claim 1 including a keying arrangement betweenthe external body of said socket and the perimeter of said opening forretaining said termination socket within said opening in said panel andfor locking said socket in place rotationally.
 3. Apparatus according toclaim 2 in which said retention of said socket in said opening iseffected by a locking ring inserted in a circumferential slot in theexternal perimeter of said socket, said ring bearing against said panelon the side thereof opposite the installation of said knob, and in whichsaid socket includes a shoulder bearing against said panel on theopposite side thereof, whereby said socket is axially locked inposition.
 4. Apparatus according to claim 1 including an at leastpartially radially outwardly projecting finger connected to the outerperimeter of said socket within said knob body and at least one stopring keyed to said knob body and having at least one radially inwardlyprojection oriented to engage said outwardly projecting finger at apredetermined angular position of said knob and shaft.
 5. Apparatusaccording to claim 1 having two of said stop rings stacked axially andeach having multiple peripheral keying means whereby they may beseparately keyed to said knob body to provide first and second angularlimits of operation of said knob and shaft.
 6. Apparatus according toclaim 4 in which said knob body is composed of at least two axiallyassembled hollow parts, a first of said parts containing said stop ring,whereby said knob may be assembled by emplacing said first part inproximate position over said panel opening and inserting said socketthrough said first part and said panel.
 7. Apparatus according to claim6 including a second hollow knob body part axially snap-fitted into saidfirst part, said second part including an internal surface in a planenormal to the axis of said knob to face said termination socket flangeto carry said resilient means bearing against said circular crosssection member.
 8. Apparatus according to claim 7 in which said shaftlock means are included in said second part, whereby said knob may befurther assembled by emplacing said rolling member of circular crosssection against said engaging contour and emplacing and locking saidsecond part to said shaft thereby bringing said resilient means to bearagainst said circular cross section member.
 9. Apparatus according toclaim 8 having at least two circular cross section members substantiallydiametrically opposite in position along said engaging contour and saidmembers are balls.
 10. Apparatus according to claim 9 in which saidresilient means comprises a pressure ring inserted against said ballsopposite said engaging contour and a helical spring bearing against saidpressure ring and caged in an annular groove inside said knob bodysecond part.